KR20220142435A - Lubrication method for hover-capable aircraft and modules of transmission units of said aircraft - Google Patents

Abstract

An aircraft (1) is described, said aircraft comprising a transmission unit (9) with first modules (11, 13, 15) and a lubrication system (25, 25'), said first modules (11, 13) , 15) is a casing 20; and a movable member (17, 18, 19), said lubrication system (25, 25') comprising: a header (26); a nozzle (27, 28) to which a lubricating fluid is supplied and designed to supply a lubricating fluid inside the casing (20) of the first module (11, 13, 15); a collection tank (30, 100') for the lubricating fluid injected by the nozzle (27, 28); and recirculation means (35) designed to recirculate said lubricating fluid from said collection tank (30, 100') to said supply header (26), said first module (11, 13, 15) comprising said header ( 26) in the first configuration in which the outflow of the lubricating fluid from the module 11 to the recirculation means 35 is activated when the pressure of the lubricating fluid therein is greater than a threshold value and in the header 26 and valves ( 60 , 60 ′) available in a second configuration for fluidically isolating the module ( 11 ) from the recirculation means ( 35 ) when the pressure of the lubricating fluid is less than the threshold value.

Description

Lubrication method for hover-capable aircraft and modules of transmission units of said aircraft

This patent application claims priority to European Patent Application No. 19219920.6, filed on December 27, 2019, the entire disclosure of which is incorporated herein by reference.

The present invention relates to hover-capable aircraft, in particular to convertiplanes or helicopters.

The invention also relates to a method for lubricating a module of a transmission unit of a hover-capable aircraft.

As is known, helicopters are generally designed to transmit drive power from one or more turbines to a main rotor and/or tail rotor, and/or from the turbine to a plurality of auxiliary devices, for example of a flight instrument. It is equipped with a transmission device intended to provide the power required for operation.

In turn, the transmission unit includes a plurality of movable members coupled to each other including a plurality of gears.

In a known manner, a lubricating fluid, generally oil, circulates inside the transmission unit to lubricate the movable member of the transmission unit and cool the aforementioned movable member.

The transmission unit is:

- a plurality of mutually successive stages; and

- a lubrication system designed to lubricate a specific area and a movable member to be lubricated of the aforementioned module;

More specifically, each pair of gears forms a corresponding stage of the transmission unit.

The transmission unit, in turn,

- a casing defining a housing shell; and

- one or more stages housed inside said casing.

According to a first solution known as "splash lubrication", the module is filled with lubricant to a certain level. The lubricant partially covers the gears. As a result, actuation of the gear releases lubricant towards the area of the module to be lubricated.

According to a further solution known as "force-feed lubrication", the lubrication system comprises a recirculation circuit which carries the lubricating oil to and from the casing of each module.

The recirculation circuit, in turn,

- Lubricant collection header for lubricating oil;

- a plurality of nozzles lubricated by a pump and designed to inject lubricating oil under pressure into the area of the module to be lubricated; and

- Includes a transfer pump that sucks and pressurizes the lubricant sprayed from the nozzle and recirculates it to the nozzle.

A “force-feed lubrication” solution may in turn be of the wet-sump or dry-sump type.

In the wet-sump solution, the casing of the module defines a respective collection tank for the lubricating oil injected by the nozzles. The transfer pump sucks this lubricant from the tank in the casing.

In the dry sump solution,

- the lubrication system includes an additional pump marked as a return pump common to all modules, and

- Common to all modules, including a tank, separate from the module's casing and fluidly connected to the aforementioned casing.

A return pump draws lubricant from the casing and makes it available in a common tank.

The transfer pump draws lubricating oil from this common tank separated from the casing and delivers it to the common header.

In all of the solutions described above, there is a risk that the pressure of the lubricant will drop below a threshold level, for example if the lubrication system fails.

In such a situation, there is a risk of impeding the correct operation of the transmission unit and impairing the operational capabilities of the helicopter.

Accordingly, there is a need in the industry to maintain a certain level of operation of the modules of the transmission unit, even in the event of a failure of the lubrication system.

The industry also recognizes the need to quickly identify and signal fault conditions in lubrication systems.

EP-A-0068677 discloses a helicopter transmission system comprising a gearbox comprising a gearcase with a hollow stub axle through which the operating load is transferred from the main holding rotor to the fuselage structure. One or more input reduction gear trains are individually supported on hollow lobe portion(s) supported from the axle, said or each lobe portion having a separate lubricating oil sump and a circulation configured to circulate lubricating oil to a respective gear train have the means Preferably, interconnection means are provided for connecting each individual sump, and the valve means are configured to maintain the flow of lubricating oil in case of loss of oil in one of the sumps.

It is an object of the present invention to manufacture a hover-capable aircraft capable of satisfying at least one of the above-mentioned requirements in a simple and low-cost manner.

The above object is achieved by the invention as far as it relates to a hover-capable aircraft as defined in claim 1 .

The invention also relates to a method for lubricating a module of a transmission unit of a hover-capable aircraft as defined in claim 15 .

For a better understanding of the present invention, two preferred embodiments are described below, purely by way of non-limiting example and with reference to the accompanying drawings:
1 is a perspective view of a hover-capable aircraft made in accordance with the teachings of the present invention, with parts removed for clarity;
- Figure 2 is a functional diagram of a first embodiment of a lubrication system integrated in the transmission unit of the helicopter of Figure 1;
3 and 4 show the valve of the lubrication system of FIG. 2 in cross section with parts removed for clarity in their respective operating configurations;
- Figure 5 is a functional diagram of a second embodiment of a lubrication system integrated in the helicopter of Figure 1;
- Figures 6 and 7 are longitudinal cross-sectional views of the valve of the lubrication system of Figure 5, with parts removed for clarity;

Referring to Figure 1, reference numeral 1 basically denotes a helicopter comprising:

- fuselage (2);

- one or more turbines 5 equipped with each output shaft 10;

- a main rotor (3) located on the upper part of the body (2) and rotatable about an axis (A); and

- an anti-torque rotor (4) located at the tail end of said body (2) and rotatable about axis (B) and transverse to axis (A).

Each rotor 3 , 4 in turn comprises a respective mast 6a , 6b to which a respective blade 7 , 8 hinges.

The helicopter 1 further comprises a transmission unit 9 known per se, which transmits motive power from the turbine 5 to the masts 6a, 6b to permit operation of the respective rotors 3 , 4 .

In turn, the transmission unit 9 comprises a plurality of movable members, in particular gears, interposed between the turbine 5 and the masts 6a, 6b.

The transmission unit 9 further comprises a plurality of stages formed by an associated pair of the aforementioned gears, each of which meshes with one another.

The transmission unit 9 further comprises:

- a pair of input gears 17 for transmitting motion from each output shaft 10 to each counter shaft 12; and

- the main gear train 18, which transmits motion from the counter shaft 12 to the mast 6a.

The transmission unit 9 further comprises:

- counter shaft 14 driven by gear train 18; and

- a pair of gears 19 that transmit motion from the counter shaft 14 to the mast 6b of the rotor 4 .

A pair of gears 17 , 19 meshing with each other and a gear train 18 form respective stages of the transmission unit 9 .

The transmission unit 9 further comprises a plurality of modules 11 , 13 , 15 .

Each module 11 , 13 , 15 basically includes ( FIG. 2 ):

- one or more pairs of gear trains 18 and respective gears 17 , 19 meshing with each other;

- a casing 20 (shown only schematically) for accommodating an associated pair of gears 17 , 19 and a gear train 18 .

Referring to FIG. 2 , the helicopter 1 further comprises a lubrication system 25 designed to convey the lubricant to a specific area of the transmission unit 9 .

In the case shown in FIG. 2 , the lubrication system 25 is of the wet-sump forced recirculation type.

The lubrication system 25 basically comprises:

- supply header 26 for lubricant;

- a plurality of nozzles 27 , 28 fluidly connected to the header 26 and designed to inject lubricant into the area to be lubricated of each module 11 , 13 , 15 and inside each casing 20 ; and

- a collecting sump 30 for the lubricating oil injected from the nozzles 27, 28 inside each module 11, 13, 15.

Header 26 and sump 30 are common to modules 11 , 13 , 15 .

The sump 30 is also integral with the casing 20 of the modules 11 , 13 , 15 .

The lubrication system 25 further includes a recirculation circuit 35 for conveying lubricating oil from the sump 30 to the header 26 .

The recirculation circuit 35 in turn comprises:

- a pair of pumps 36 having each inlet 37 fluidly connected to the sump 30;

- a pair of non-return valves 38 fluidly connected to each outlet 39 of each pump 36;

- one or more drain valves 40 connected to the check valve 38 and the header 26;

- filter 42 connected to drain valve 40; and

- a cooler 43 interposed between the filter 42 and the header 26 .

The recirculation circuit 35 further comprises:

- a bypass valve 49 fluidly interposed between the drain valve 40 and the cooler 43 to bypass the filter 42; and

- a thermostatic bypass valve 50 interposed between the filter 42 and the header 26 to bypass the cooler 43 .

Since the modules 11 are identical to each other, only one module 11 will be referred to in the following description.

Advantageously, the module 11 is

- in a first configuration (FIG. 3) allowing the outflow of lubricant from module 11 to recirculation circuit 35 when the pressure of lubricant inside header 26 is greater than a threshold value; and

- a second configuration that fluidly isolates the module 11 from the recirculation circuit 35 and permits maintaining the lubricating fluid inside the casing 20 when the pressure of the lubricating oil inside the casing 20 is below a threshold value (Fig. 4) from

Available valve 60 .

More specifically, lubricating oil is normally present inside the header 26 at a pressure above a threshold to maintain the valve 60 in the first configuration.

Conversely, when the pressure of the lubricating fluid drops to a value below a threshold value, for example in the case of a failure of the lubrication system 25 , the valve 60 moves from the first configuration to the second configuration.

When the valve 60 is arranged in the second configuration ( FIG. 4 ), the casing 20 of the module 11 is substantially sealed and the lubricant level inside the casing 20 remains substantially constant, so that the lubricant is supplied to the module 11 . The lubrication of the module 11 is preserved by the fact that it is projected towards the area to be lubricated by the gear 17 included in 11 .

In other words, if the lubrication system 25 fails, the arrangement of the valve 60 in the second configuration causes a passage from the forced supply lubrication of the casing 20 to the splash lubrication of the casing 20 . do.

In the illustrated embodiment, the valve 60 is of the automatic type, ie it has no external control members.

More specifically, the valve 60 automatically moves from the first configuration to the second configuration depending on the pressure inside the header 26 .

3 and 4 , the casing 20 includes:

- a lower part 61 in which the lubricant sprayed by the nozzle 27 is collected and accommodates the valve 60; and

- opening 62 fluidly connected to the sump 30 (not shown in FIG. 3 ) and the lower part 61 .

In the case shown, the opening 62 is circular.

The valve 60 basically includes:

- the shell 65 fixed to the lower part 61 of the casing 20;

- a plunger 66 sliding inside the shell 65 along the axis E between a first position ( FIG. 3 ) and a second position ( FIG. 4 ); and

- a spring 69 interposed between the shell 65 and the plunger 66 and designed to resiliently push the plunger 66 towards the second position.

In the case shown, the spring 69 is of the helical type.

The plunger 66 includes a stem 70 interposed axially between each opposite axial end 67 , 68 and an end 67 , 68 .

End 68 is flange-shaped, which is larger in diameter than stem 70 and projects radially from stem 70 in a cantilever manner corresponding to the diameter of opening 62 .

The plunger 66 further includes a flange 77 adjacent the end 67 and having a larger diameter than the stem 70 .

The valve 60 further comprises:

- chamber 74 (FIG. 2) delimited by shell 65 and fluidly connected to header 26 by fluid line 85; and

- chamber 75 fluidly connected to chamber 74 by a plurality of openings 76 .

The chamber 75 is delimited by the shell 65 and the flange 77 of the plunger 66 and thus has a variable volume depending on the position of the plunger 66 along the axis E.

In the case shown, the openings 76 are axially and angularly equispaced about the axis E.

The valve 60 further includes a plurality of openings 72 made in the shell 65 .

The openings 72 are angularly equally spaced around the axis E.

End 67 contacts spring 69 and end 68 is received within lower portion 61 .

The plunger 66 is subjected to opposing forces created by the pressure of the lubricating oil inside the chamber 75 on the flange 77 and the spring 69 acting on the end 67 . This pressure is equal to the pressure inside the header 26 .

The valve 60 is configured in the following way:

- the action of lubricating oil pressure on the flange 77 overcomes the elastic action of the spring 69 when the pressure is higher than a threshold to bring the valve 60 into the first configuration and the plunger 66 to the first position (Fig. 3). ) to move

- the action of lubricating oil pressure on the end 67 is not sufficient to overcome the elastic action of the spring 69 when the pressure is lower than the threshold, thereby moving the valve 60 to the second configuration and the plunger 66 to the second configuration. position (Fig. 4).

In particular, when the plunger 66 is in the first position, the end 68 is spaced from the opening 62 through which lubricant oil continues to flow from the casing 20 to the sump 30 .

When the plunger 66 is in the second position, the end 68 seals against the opening 62 to prevent the flow of lubricant through the opening 62 .

When the plunger 66 is in the first position and the valve 60 is in the first configuration ( FIG. 3 ), the opening 72 is located between the flange 77 and the chamber 74 along the axis E. . In this manner, chamber 75 is in fluid communication with opening 72 .

Conversely, when the plunger 66 is in the second position and the valve 60 is in the second configuration ( FIG. 4 ), the flange 77 moves along the axis E with the opening 72 and the chambers 74 , 75 . located between

In this way, chamber 75 is fluidly isolated from opening 72 .

Chamber 75 has a larger volume when plunger 66 is in the first position in FIG. 3 and has a smaller volume when plunger 66 is in the second position in FIG. 4 .

The shell 65 further includes a chamber 90 that receives the spring 69 and is in fluid communication with the lower portion 61 of the casing 20 through a plurality of openings 91 formed in the shell 65 .

As such, the lubricating oil inside the chamber 90 is at the same pressure as the lubricating oil inside the lower portion 61 of the casing 20 . Consequently, the resultant force acting on the plunger 66 from the pressure of the lubricant oil received in the chamber 90 and acting on the end 68 is null.

Chamber 90 is in fluid communication with opening 72 when plunger 66 is in the second position shown in FIG. 4 .

The lubrication system 25 includes a pressure sensor 150 designed to sense the pressure inside the opening 72 of the shell 65 .

When the valve 60 is disposed in the second configuration and the plunger 66 is in the second position ( FIG. 4 ), the opening 72 is fluidly isolated from the chamber 75 and fluidly connected to the casing 20 . Connected.

The pressure sensor 150 detects a pressure value of the lubricant that is less than the threshold and equal to the pressure of the lubricant in the casing 20 and therefore becomes substantially zero.

Conversely, when the valve 60 is arranged in the first configuration and the plunger 66 is in the first position ( FIG. 3 ), the opening 72 is fluidly connected to the chamber 75 . Consequently, the pressure sensor 150 detects a pressure value that is greater than the threshold and equal to the pressure value in the chamber 75 and thus equal to the pressure value in the header 26 .

In this way, the pressure reading provided by the pressure sensor 150 provides a clear indication of whether:

- whether it is desirable to quickly land the helicopter 1 as the valve 60 is in the second configuration, or

- whether the valve 60 is in the first configuration and the lubrication system 15 is operating correctly.

In the case shown, module 13 does not include valve 60 .

In use, the turbine 5 rotationally drives the masts 6a , 6b of the respective rotors 3 , 4 through the transmission unit 9 .

Specifically, the gear 17 of the module 11 transmits motion from the output shaft 10 of each turbine 5 to the counter shaft 12 , and the gear 18 of the main module 13 is the counter shaft Transmits motion from (12) to mast (6a), and gear (19) of module (15) transmits motion from countershaft (14) to mast (6b).

The lubrication system 25 ensures correct lubrication of the modules 11 , 13 , 15 and the respective gears or gear trains 17 , 18 , 19 .

In more detail, the lubricating oil contained in the header 26 is conveyed to the nozzles 27 and 28 and is sprayed by the nozzles into the lubrication target areas of the modules 11 , 13 and 15 and the inside of each casing 20 .

Lubricating oil also flows from header 26 through fluid line 85 to chambers 74 and 75 of valve 60 .

This lubricant is then collected in the sump ( 30 ) and conveyed back to the header ( 26 ) via a recirculation circuit ( 35 ).

More specifically, the pump 36 draws lubricating oil from the sump 30 and pumps it to the check valve 38 , the drain valve 40 , the filter 42 , and the cooler 43 .

The operation of the lubrication system 25 is described below only with respect to the module 11 and starts with the pressure of the lubricating oil greater than a threshold value.

This condition substantially corresponds to the normal and correct operating condition of the lubrication system 25 .

In this state, the valve 60 is in the first configuration and the plunger 66 is in the first position (FIG. 3). Header 26 is also fluidly connected to chamber 74 and to chamber 75 through opening 76 .

In this state, the pressure exerted by the lubricant inside the chamber 75 acts on the flange 77 of the plunger 66 and overcomes the action of the spring 69 on the end 67 .

An opening 72 is also interposed between the flange 77 and the chambers 74 , 75 along the axis E. The opening 72 is thus fluidly connected to the chambers 74 , 75 .

Accordingly, the plunger 66 opens the opening 62 to allow lubricating oil to flow from the casing 20 to the sump 30 .

If, for example, a failure of the lubrication system 25 causes the lubricating oil pressure inside the header 26 and chamber 75 to drop below a threshold, the valve 60 will automatically move to the second configuration and the plunger 66 will It automatically moves to the second position (FIG. 4) to close and seal the opening 62.

This occurs because the resilient force of the spring 69 on the end 67 exceeds the force exerted by the pressure of the lubricant in the chamber 75 on the flange 77 of the plunger 66, which pushes the plunger into the second position. .

In this state, the flange 77 is interposed between the opening 72 and the chambers 74 , 75 axially along the axis E. The opening 72 is thus fluidly isolated from the chamber 74 .

At this point, the lubricant remains trapped inside the casing 20 of the module 11 and forms an oil bath in which the gear 17 is at least partially submerged.

The operation of the gear 17 projects the lubricating oil into the lubrication target area of the module 11 to effectively implement splash lubrication.

The pressure sensor 150 detects the pressure at the opening 72 and enables continuous monitoring of whether the valve 60 is in the first configuration or the second configuration.

5-7, reference numeral 25' denotes a lubrication system 25 according to another embodiment of the present invention.

The lubrication system 25' is similar to the lubrication system 25 and only differences will be described below; Wherever possible, identical or equivalent parts of the lubrication systems 25, 25' are denoted by the same reference numerals.

In particular, lubrication system 25' differs from lubrication system 25 in that it is a dry-sump, forced recirculation lubrication system.

Lubrication system 25' also differs from lubrication system 25 in that it includes:

- common to modules 11 , 13 , 15 , fluidically isolated from the casing 20 of these modules 11 , 13 , 15 and fluidly interposed between the aforementioned casing 20 and the pump 36 . tank 100';

- a respective inlet port 102' associated with each stage 11, 13, 15 and fluidly connected to a respective casing 20 and a plurality of outlet ports 103 fluidly connected to the tank 100' ') with a plurality of recovery pumps 101'; and

- a fluid line 104' interposed between the valve 60' of the module 11 and the nozzle 155' of the module 11.

In the illustrated case, the tank 100 ′ is fluidly separated from the casing 20 , in particular arranged outside the casing 20 .

Alternatively, the tank 100' may be arranged inside the casing 20 but still fluidly distinct therefrom.

Lubrication system 25' differs from lubrication system 25 in the following respects:

- the valve 60 ′ associated with the module 11 is arranged outside the casing 20 ; and

- The valve 60' of the module 11 is a three-way valve fluidly connected to the discharge port 103' associated with the same module 11, the tank 100', and the casing 20.

More specifically, when the valve 60' is arranged in the first configuration (FIG. 6), the discharge port 103' of the recovery pump 101' of the module 11 is fluidly connected to the tank 100'. to fluidly isolate the exhaust port 103' and the fluid line 104' of the module 11.

Conversely, when valve 60' is disposed in the second configuration (FIG. 7), valve 60' fluidly isolates discharge port 103' of recovery pump 101' from tank 100'. and fluidically connect the outlet port 103' to the fluid line 104' and consequently to the casing 20.

6 and 7, valve 60' includes:

- shell 110';

- a plunger 111 ′ sliding inside the shell 110 ′ along the axis F between a first position ( FIG. 6 ) and a second position ( FIG. 7 ); and

- a spring 112' interposed between the shell 110' and the plunger 111' and designed to resiliently push the plunger 111' towards the first position.

In the case shown, the spring 112' is of the helical type.

The plunger 111' includes:

- two extensions 113 ′, 114 ′ axially opposite each other and sliding sealingly inside the shell 110 ′, and

- a stem 115' axially connecting the extensions 113', 114' and having a smaller diameter than the shell 110'.

In particular, the extension 113' abuts the spring 112'. Expansion 114' and shell 110' define chamber 116'. Chamber 116 ′ is axially open opposite extension 114 ′ and is fluidly connected to header 26 .

As a result, the extension 114 ′ is under the pressure of the lubricating oil inside the header 26 .

The action of this pressure pushes the plunger 111 ′ towards the first position ( FIG. 6 ).

In particular, in the first position of the plunger 111 ′ in FIG. 6 , the spring 112 ′ is compressed. Conversely, in the second position of the plunger 111' of FIG. 7, the spring 112' is extended.

The shell 110' includes three openings 125', 126', 127' which pass through the openings in a radial direction with respect to the axis F and are axially staggered from one another.

More specifically, opening 125' is fluidly connected to tank 100', opening 126' is fluidly connected to recovery pump 101', and opening 127' is fluidly connected to fluid line 104'. fluidly connected.

In the case shown, apertures 126' are diametrically opposite apertures 125' and 127'.

In this way, the plunger 111 ′ is subjected to the opposing force generated by the spring 112 ′ and the pressure of the lubricant inside the header 26 .

The valve 60' is sized such that the force generated in the extension 114 overcomes the elastic action of the spring 112' when the pressure is greater than a threshold value. In this situation, enlargement 114' blocks opening 127' and plunger 111' leaves openings 125', 126' open (FIG. 6). In this state, the valve 60' is arranged in the first configuration and the plunger 111' is arranged in the first position (FIG. 6).

Conversely, when the pressure of the lubricant is less than the threshold value, the elastic action of the spring 112' exceeds the action exerted on the extension 114' by the pressure of the lubricant. In this condition, enlarged portion 113' blocks opening 125' and plunger 111' leaves openings 126' and 127' open (FIG. 7). Consequently, the valve 60' is arranged in the second configuration and the plunger 111' is arranged in the second position (FIG. 7).

In a manner similar to the lubrication system 25 , the lubrication system 25 ′ includes a pressure sensor 150 ′ designed to sense the pressure inside the opening 151 ′ of the shell 110 ′.

More specifically, openings 151' are through openings in a radial direction with respect to axis F and are axially staggered with respect to openings 125', 126', 127'.

When the valve 60' is arranged in the second configuration and the plunger 111' is in the second position (FIG. 7), the enlarged portion 114' blocks the opening 151'.

As a result, the pressure sensor 150' detects a pressure value of substantially zero (null).

Conversely, when the valve 60' is arranged in the first configuration and the plunger 111' is in the first position (FIG. 6), the enlarged portion 114' opens the chamber 116' and thus the header 26. and leaving the opening 127' in fluid communication with the open.

Consequently, the pressure sensor 150 ′ detects a pressure value substantially equal to the pressure value of the lubricant in the header 26 .

The pressure reading provided by the pressure sensor 150' in this way provides a clear indication of whether:

- it is desirable to quickly land the helicopter 1 because the valve 60' is in the second configuration, or

- The valve 60' is in the first configuration and the lubrication system 15 is operating correctly.

In the case shown, modules 13 and 15 do not include valve 60'.

The operation of the lubrication system 25' is that of the lubrication system 25 in that the recovery pump 101' sucks the lubricating oil from the casing 20 and conveys it to the tank 100' when the pressure of the lubricating oil is greater than a threshold value. different from working.

In this state, valve 60' is arranged in a first configuration, wherein the valve fluidly connects recovery pump 101' to tank 100' and connects recovery pump 101' to fluid line 104'. ) is fluidly isolated from

More specifically (FIG. 6), the pressure action of the lubricant on the extension 114' is such that it overcomes the elastic action of the spring 112'.

Consequently, enlargement 114' blocks opening 127' and plunger 111' leaves openings 125', 126' open (FIG. 6).

Conversely, if the pressure of the lubricating oil in the header 26 is below a threshold, for example due to a failure of the lubrication system 25', the valve 60' is automatically moved to the second configuration. In this second configuration (FIG. 7), valve 60' fluidly connects recovery pump 101' to fluid line 104' and fluidly connects recovery pump 101' from tank 100'. isolate with

As a result, the lubricating oil reaches the nozzle 155', which again injects the lubricating oil into the casing 20, ensuring lubrication of the module 11 even when the pressure of the lubricating oil is less than the threshold value.

More specifically ( FIG. 7 ), the elastic action of the spring 112 ′ overcomes the pressure action of the lubricant on the extension 114 ′. In this state, the enlarged portion 113' blocks the opening 125' and the plunger 111' leaves the openings 126' and 127' open.

A pressure sensor 150' senses the pressure at the opening 151' and enables continuous monitoring of whether the valve 60' is in the first configuration or the second configuration.

Looking at the characteristics and lubrication method of the helicopter 1 according to the present invention, the advantages that can be obtained through this are clear.

In particular, the valves 60 , 60 ′ of the module 11 are arranged in the first half configuration ( FIGS. 3 , 4 , 6 and 7 ) when the pressure of the lubricant inside the header 26 is greater than or less than a threshold value. .

As a result, in the event of a failure of the lubrication system 25, 25' resulting in a pressure drop in the lubricating oil, the valves 60, 60' prevent the lubricating oil from returning to the pump 36 and injecting the lubricating oil inside the casing 20. keep

In this way, in the event of a failure of the lubrication system 25, 25', the gear 17 contained inside the module 11 remains submerged in the lubricating oil bath, and due to its movement, this lubricating oil lands on the area to be lubricated. is projected towards.

That is, when the valves 60 and 60' move to each of the second configurations, the module 11 is "sealed" to prevent leakage of lubricant and effectively implements the splash lubrication of the module 11. .

The valves 60, 60' are automatic, so as soon as the pressure value inside the header 26 falls below a threshold, in a repeatable and efficient manner, without the need for expensive dedicated control devices, the valves 60, 60' ) moves to the relevant second configuration.

A sensor 150 is operatively connected to the openings 72 and detects pressure values at the openings 72 and provides a signal indicating whether the valve 60 is in the first or second configuration.

Similarly, a pressure sensor 150' is operatively connected to the opening 155' of the valve 60' and provides a signal indicating whether the valve 60' is in the first or second configuration.

In this way, when the valves 60, 60' are in the second configuration, the readings provided by the pressure sensors 150, 150' indicate the pressure drop in the lubricating oil and consequent failure of the lubrication system 25, 25'. clearly indicates

This warns the pilot to land quickly.

Conversely, the reading provided by the pressure sensor 150' when the valve 60' is in the first configuration indicates that the pressure inside the header 26 and the lubrication system 25' are operating correctly.

Finally, it is clear that modifications and variations may be made to the helicopter 1 and to the lubrication method described and illustrated herein without departing from the scope defined in the claims.

In particular, the aircraft 1 ′ may be a convertible aircraft rather than a helicopter.

Modules 13 , 15 may also include valves 60 , 60 ′.

Finally, the pressure sensors 150, 150' may be replaced with pressure switches designed to generate a first signal when a pressure greater than a threshold is sensed and a second signal when a pressure less than a threshold is sensed. .

Claims (15)

A hover-capable aircraft (1) comprising:
- a motion transmission unit 9 formed by at least a first module 11 , 13 , 15 ; and
- a lubrication system (25, 25') designed to lubricate the transmission unit (9);
The first module (11, 13, 15), in turn,
- casing (20); and
- a movable member (17, 18, 19) accommodated inside the casing (20),
The lubrication system 25, 25' comprises:
- a supply header (26) for said lubricating fluid;
- an associated movable member (17) capable of supplying said lubricating fluid from said supply header (26) and designed to supply said lubricating fluid inside said casing (20) of said first module (11, 13, 15); at least one nozzle (27, 28) enabling lubrication of 18, 19;
- a collection tank (30, 100') for said lubricating fluid injected by said nozzles (27, 28); and
- a hover-capable aircraft comprising recirculation means (35) designed to recirculate said lubricating fluid in said collection tank (30, 100') to said supply header (26),
At least the first module ( 11 , 13 , 15 ) comprises a valve ( 60 , 60 ′) available in a first configuration, wherein the outflow of the lubricating fluid from the module ( 11 ) to the recirculation means ( 35 ) is enabled when the pressure of the lubricating fluid inside the supply header 26 is greater than a threshold value;
The valve ( 60 , 60 ′) is available in a second configuration, wherein it is fluidically isolating the module ( 11 ) from the recirculation means ( 35 ) and discharging the lubricating fluid inside the supply header ( 26 ). A hover-capable aircraft (1), characterized in that it makes it possible to keep the lubricating fluid inside the casing (20) when the pressure is less than the threshold value. The method of claim 1,
The valves 60 , 60 ′ are automatic and the movement of the valves 60 , 60 ′ between the first and second configurations is automatically determined by the value of the pressure inside the feed header 26 . A hover-capable aircraft (1), characterized in that it becomes 3. The method of claim 2,
The valves 60, 60', in turn,
- a shell 65, 110' fixed against the casing 20;
- a plunger (66, 111') sliding inside said shell (110') between first and second positions corresponding to said first configuration and said second configuration respectively;
- elastic means (69, 112') interposed between the shell (65, 110') and the plunger (66, 111') and designed to resiliently push the plunger (66, 111') towards the second position ); and
- defined between said shell (65) and said plunger (66), fluidly connected to said supply header (26) and, in use, as opposed to being exerted by said resilient means (69), in said first position; A hover-capable aircraft (1), characterized in that it comprises a chamber (74, 75; 116') configured to apply an action directed toward the plunger (66, 111'). 4. The method according to any one of claims 1 to 3,
the transmission unit (9) comprises at least a second module (13);
the supply header 26 is common to the first and second modules 11 and 13;
The tank (30) is shared between the first and second modules (11, 13) and is defined by the casing (20) of at least one of the first and second modules (11, 13), the A hover-capable aircraft (1), characterized in that it is a sump designed to be filled with a lubricating fluid. 5. The method of claim 4,
the casing (20) comprises a section (61) for receiving the valve (60) and a fluid passageway (62) fluidly interposed between the section (61) and the collection tank (30);
said at least one nozzle (27) is configured to supply said lubricating fluid in said zone (61);
the plunger (66), when disposed in the first position, leaves the fluid passageway (62) open and allows the lubricating fluid to flow from the casing (20) into the tank (30);
A hover-capable aircraft (1) characterized in that the plunger (66), when disposed in the second position, blocks the fluid passageway (62) and retains the lubricating fluid in the casing (20) in use. . 3. The method according to claim 1 or 2,
- a recovery pump (101') having an inlet port (102') and an outlet port (103') fluidly connected to the casing (20); and
- an additional tank (100') fluidly isolated from the casing (20); and
- a fluid line (104') extending between the valve (60') and the casing (20);
The recirculation means (35) is a transfer pump (36) having an inlet port (102') fluidly connected to the addition tank (100') and an outlet port (103') fluidly connected to the supply header (26). comprising;
the valve 60' is interposed between the discharge port 103' of the recovery pump 101' and the addition tank 100';
The valve 60', when arranged in the first configuration, fluidly connects the discharge port 103' of the recovery pump 101' to the additional tank 100', the fluid line fluidly isolate the discharge port (103') of the recovery pump (101') from (104');
The valve 60', when arranged in the second configuration, fluidly connects the outlet port 103' to the fluid line 104' and connects the outlet port 103' to the additional tank. A hover-capable aircraft (1), characterized in that it is fluidly isolated from (100'). 7. The method of claim 6,
The valve 60' is:
- a first opening (127') fluidly connected to said fluid line (104');
- a second opening (126') fluidly connected to said discharge port (103') of said recovery pump (101'); and
- a third opening (125') fluidly connected to the tank (100'),
When the plunger 111' is arranged in the first position and the valve 60' is arranged in the first configuration, the plunger 111' blocks the first opening 127' and closes the first opening 127'. put the second and third openings 125', 126' in fluid communication with each other;
When the plunger 111' is arranged in the second position and the valve 60' is arranged in the second configuration, the plunger 111' blocks the third opening 125' and closes the third opening 125'. A hover-capable aircraft (1), characterized in that the first and second openings (127', 126') are in fluid communication with each other. 8. The method of claim 7,
A hover-capable aircraft (1), characterized in that the valve (60') is arranged outside the first module (11). 9. The method according to any one of claims 1 to 8,
and a sensor (150, 150') designed to provide an indication as to whether the valve (60, 60') is in the first or second configuration. 10. The method of claim 9,
wherein said sensor (150, 150') is a pressure sensor or pressure switch and is configured to provide a signal related to the pressure in said header (26) when said valve (60, 60') is in said first configuration. which, hover-capable aircraft (1). 11. The method of claim 10,
10. According to any one of claims 7 to 9, the shell (66, 110') has a fourth opening (72, 155') operatively connected to the sensor (150, 150'). including,
The hover-capable aircraft (1), characterized in that the sensor (150, 150') is configured to detect the pressure inside the first opening (72, 155'). 12. The method of claim 11,
11. A method according to any one of claims 3 to 10, wherein said first opening (72) is fluidly connected to said chamber (74, 75) when said plunger (66) is in said first position, A hover-capable aircraft (1), characterized in that the plunger (66) is fluidly connected to the casing (20) when in the second position. 12. The method of claim 11,
the plunger (111') in use closes the fourth opening (155') when the valve (60') is in either the first or second configuration;
When the valve 60' is in the other of the first or second configuration, the plunger 111' leaves the fourth opening 155' open and closes the fourth opening 155'. A hover-capable aircraft (1), characterized in that it is placed in fluid communication with the header (26). 14. The method according to any one of claims 1 to 13,
- at least one pushing unit (5) with each output member (10); and
- at least one rotor (3) operatively connected to said output member (10);
the rotor 3 comprises a mast 6a, 6b;
The transmission unit 9 comprises:
- a pair of first gears (17) interposed between said output member (10) and at least one intermediate shaft (12);
- at least a pair of second gears (18) interposed between the intermediate shaft (12) and the mast (6a, 6b);
the first module 11 comprises each of the first gears 17;
the transmission unit (9) further comprises a second module (13) for receiving a train of the second gear (18);
characterized in that said supply header (26) is common to said first and second modules (11, 13); and/or
A hover-capable aircraft (1), characterized in that the aircraft is a helicopter or a convertible aircraft. A method for lubricating modules (11, 13, 15) of a transmission unit (9) of a hover-capable aircraft (1);
The modules (11, 13, 15) in turn,
- casing (20); and
- a movable member (17, 18, 19) accommodated inside the casing (20);
The method is:
i) collecting said lubricating fluid in a supply header (26);
ii) supplying the lubricating fluid contained in the header 26 into the casing 20 to enable lubrication of the movable members 17, 18, 19 of the modules 11, 13, 15 to do; and
iii) recirculating the lubricating fluid conveyed inside the casing (20) to the header (26),
iv) arranging the valves ( 60 , 60 ′) of the module ( 11 , 13 , 15 ) in a first configuration, wherein the header ( 26 ) when the pressure of the lubricating fluid inside the header ( 26 ) is greater than a threshold value allowing recirculation of the lubricating fluid to (26); and
v) arranging the valves (60, 60') in a second configuration, wherein the recirculation is prevented when the pressure of the lubricating fluid inside the supply header (26) is less than a threshold value and inside the casing (20) retaining the lubricating fluid in

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